The present invention relates to magnetic sensors, and in particular to sensors for cyclic lubricant feeders utilizing reciprocating distributor valves, the sensor being a magnetic sensor for sensing the movement of a reciprocating valve.
A cyclic lubricant distributor valve is disclosed, for example, in U.S. Pat. No. 4,312,425 and U.S. Pat. No. 3,921,760. These distributor valves utilize a block or blocks having a spool bore for holding and guiding a reciprocating spool therein. The spool has cylindrical formations along its length to form various flow paths between formations. A plurality of oil passages are connected into the spool bore along its length. The spool bore and ports form a plurality of oil channels which are activated and deactivated according to the movement of the spool within the spool bore. The distributor valve thus distributes oil in pulses to a plurality of users such as bearings in a machine.
It is desirable for monitoring and/or control to sense the movement of a spool within the spool bore. It is known, such as from U.S. Pat. No. 4,572,331, to provide a rod projecting outward of a distributor block and connected to a reciprocating spool, the rod contacting a micro switch to open and close according to the spool position. However, such a construction requires a packing or seal at the block to seal the reciprocating rod.